1. Field of the Invention
Embodiments of the present invention generally relate to a method, device, and system for sensing interference in a display device having integrated input sensing.
2. Description of the Related Art
Input devices including proximity sensor devices (also commonly called touchpads or touch sensor devices) are widely used in a variety of electronic systems. A proximity sensor device typically includes a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location, and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices are often used as input devices for larger computing systems, such as opaque touchpads integrated in or peripheral to notebook or desktop computers. Proximity sensor devices also are often used in smaller computing systems, such as touch screens integrated in cellular phones.
Proximity sensor devices are typically used in combination with other supporting components, such as display or input devices found in the electronic or computing system. In some configurations, the proximity sensor devices are coupled to, or placed in close proximity to, these supporting components to provide a desired combined function or to provide a desirable complete device package. Many commercially available proximity sensor devices utilize one or more electrical techniques to determine the presence, location and/or motion of an input object, such as a capacitive or a resistive sensing technique. However, these useful electrical sensing techniques are susceptible to interference, such as electromagnetic interference (EMI), commonly generated by the other supporting components, such as liquid crystal display (LCD) components, that are positioned near the proximity sensor device. In touch screen-type applications, since it is often desirable to have the proximity sensor information processed at a rate higher than the display refresh rate in order to better track the movement or position of an input object, EMI seen by components in the proximity sensing device may vary at any instant in time, depending on where the display device is in its refresh cycle.
Current systems have been unable to effectively measure this type of EMI, since interference measurements cannot effectively be performed during proximity sensing, and image-dependent noise associated with display updating prevents accurate interference measurements from being obtained during display-update times. Instead, current systems have commonly resorted to minimizing the magnitude of EMI by distancing EMI-generating components from proximity sensing components, adding shielding components to the device package, and/or altering the display processing method, making the resulting system more expensive and/or needlessly increasing its size and/or weight.
Therefore, there is a need for an improved method, device, and system for sensing interference in a display device having integrated input sensing.